solve

 sudoku

  step 1 2 3 4 5 6 7 8 9 10
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A very easy puzzle to get the idea of how sudoku is solved
Roger Walker
explanations:-
this is step 8


With 6's in c7 and c8 and row 1 there is only one place for a 6 in box 3 at c9r3 and the new 6 together with 6's in c6 and c2 fix the 6 in box 1 at c3r2.

The 6's in r4 and r6 with the 6 in c2 fix the 6 box 4 at c1r5.

Box 4 now has only two cells free for a 1 or a 2. Because r6 already has a 1 in it, cell c2r6 must be a 2 leaving c2r5 for the 1. (entered in step 9)

.Now we know the 1 in box 4 has to be in c2, the 1's in c3 and r7 position the 1 in box 7 in cell c1r9

This leaves two cells free in box 7 for a 2 and 7. c3 already has a 7 so c3r9 must be a 2 and therefore c1r7 a 7 and then only one space left in row 7 for a 2 (entered in step 9)

 

c1
c2
c3
 
c4
c5
c6
 
c7
c8
c9
 
 
6

 4

   
5
 
9

   
6

3
 
6
r1
box

1
2
&
3
 
3
-box 1-
6
 
6
   
-box 2-
4
 
 
9
- box 3 
6

5
r2

8
 
 
9
 
7
 
 
   
6

4
 
6
r3

9

8

3
   
4

2
 
1
 
 
 
5

7
r4
box

4
5
&
6
 
6
- box 4 
6

4
 
8
- box 5 -
7

5
   
- box 6 
9

 
r5

5
 
6

7
 
3


9
 
1
 
8

4
r6
 
1

3
 
8
 

5
 
  4

9
r7
box

7
8
&
9

4
- box 7 
9

5
 
6
- box 8
 
 
 
box 9 
 

 
r8
 
1


1
 
9

8

4
 
5

 

 
r9




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15th january 2010 © 2014